Marley Marley Class F400 User manual

/Marley Class F400 Cooling Tower /
User Manual 93-1288A

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Contents
These instructions assist in obtaining efficient, long life from Marley
counterflow cooling towers. Direct questions concerning cooling
tower operation and maintenance to your Marley sales represen-
tative. Always include your tower serial number when writing for
information or ordering parts. Look for this number on the sidewall
casing.
The following defined terms are used throughout this manual to
bring attention to the presence of hazards of various risk levels, or
to important information concerning the life of the product.
Indicates presence of a hazard which can cause severe personal
injury, death or substantial property damage if ignored.
Indicates presence of a hazard which will or can cause personal
injury or property damage if ignored.
Indicates special instructions on installation, operation or main-
tenance which are important but not related to personal injury
hazards.
Warning
Caution
Note
Note
Before Startup .............................................................................................................3
Starting Procedure .....................................................................................................4
Operation......................................................................................................................4
Tower Maintenance.....................................................................................................6
Water Treatment..........................................................................................................8
Spare Parts................................................................................................................12
Seasonal Shutdown Instructions .........................................................................12
Tower Cleaning.........................................................................................................13
Troubleshooting........................................................................................................14
Safety..........................................................................................................................15
Inspection and Maintenance Schedule...............................................................16
Inspection Checklist................................................................................................18

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Before Start-up
Among other sources, outbreaks of Legionnaires’ disease have
reportedly been traced to cooling towers. Maintenance procedures
that prevent amplification and dissemination of Legionella and other
airborne bacteria should be formulated and implemented BEFORE
systems are operated and continued reqularly thereafter to avoid
the risk of sickness or death
CLEANING–New installations should be cleaned and treated with biocides
by a water treatment expert before startup. Remove any dirt and trash which
has accumulated in the cold water basin. Remove any sediment from the cold
water collection basin, sump, and screens. Use a water hose to flush cold
water collection basins.
OPERATE WATER SYSTEM–Start the circulating water pumps. Increase the
flow of circulating water gradually to match design water flow rate. Circulate
water over the cooling tower continuously for several days before starting
the mechanical equipment and placing the cooling tower into continuous
operation.
When starting in cold weather, follow procedures outlined in Cold
Weather Operation.
INSPECTION–It is imperative that all operating assemblies be inspected
before they are placed in operation. The following is a list of components to
be checked before starting the tower:
1–Check drive shaft alignment. Realign if necessary. See Marley Drive Shaft
Service Manual.
2– Check tightness of bolts in fan cylinder joints.
3–Check tightness of the following bolted joints in the fan and drive assem-
blies:
a–Fan hub clamp bolts. See Marley Fan User Manual for correct torque
setting).
b–Fan hub cover bolts.
c–Geareducer®and motor mounting bolts.
d—Drive shaft coupling and guard bolts.
4–Check Geareducer oil for sludge or water by draining off and testing a
sample as outlined in the Geareducer User Manual. Check Geareducer
oil level at “oil level” mark on the side of the case. Add oil as required. The
Note
➠
Warning

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oil level placard must be adjusted so that its “full” mark is at the same eleva-
tion as the “full” mark on the side of the Geareducer case. Check oil lines
to be sure there are no leaks. See Geareducer User Manual for oil filling
procedure and list of recommended lubricants.
5–Rotate fan by hand to be sure of free rotation and ample tip clearance. See
Fan User Manual.
6–Check motor insulation with a “Megger”. See Maintenance Section of Marley
Electric Motor User Manual.
7–Lubricate the motor according to motor manufacturer’s instructions.
8–Test run each fan separately for a short time. Check for excessive vibration
or unusual noise. If either is present, see Troubleshooting Guide on pages
14 and 15 of this manual. Fan must rotate clockwise when viewed from
above. Recheck Geareducer oil level.
9–Check functioning of make-up water supply.
10–Make sure the blowdown will carry the proper amount of water.
Starting Procedure
WATER SYSTEM–Fill the cold water collection basin and circulating water
system until the operating water level is reached. See Operation Section, below.
Prime and start the circulating water pumps. Increase the flow of circulating
water gradually to design water flow rate to avoid water hammer which could
damage the distribution piping system.
Clean the sump screens several times during the first weeks of
operation. After this, clean sump screens weekly.
When starting in cold weather, follow procedures outlined in Cold
Weather Operation.
STARTING FAN–Start the fan. After 30 minutes of operating time to permit
Geareducer oil to come up to operating temperature, check motor load with
watt meter, or take operating volt and ampere readings and calculate motor
hp. Refer to Marley Fan User Manual for instructions. Pitch fans to pull cor-
rect contract horsepower when circulating design water rate at design hot
water temperature.
Operation
Entering water temperature in excess of 125°F may result in fill
deformation.
Note
Note
Caution

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TOWER PERFORMANCE–Keep the cooling tower clean and water distribu-
tion uniform to obtain continued maximum cooling capacity.
The capacity of a cooling tower to cool water to a given cold water tempera-
ture varies with the wet-bulb temperature and the heat load applied to the
cooling tower.
As the wet-bulb temperature drops, the cold water temperature also drops.
However, the cold water temperature does not drop linearly with the wet-bulb
temperature.
A cooling tower will not control heat load. The flow rate of water circulated
through the cooling tower will determine the temperature range of cooling in
conjunction with a given heat load. The hot water and cold water temperatures
will increase with higher heat loads.
HOT WATER DISTRIBUTION SYSTEM–Maintainuniformwaterdistribution
at the nozzles (uniform spray cone). The amount of water circulated should
approximate the contract requirements and the nozzle pressure should be kept
constant. Lower pressures may indicate excessive losses in the piping system
and/or insufficient pump capacity; greater pressures might indicate clogged
nozzles and/or overpumping. If a greatly reduced water flow rate is desired, it
may be advisable to change nozzle sizes to obtain the desired pressure and
maintain proper water distribution. An SPX Cooling Technologies engineer
can advise minimum and maximum flow rates for even distribution.
COLD WATER COLLECTION BASIN–A suitable depth must be maintained
to keep the pumps from pulling air into the line. The amount of “make-up”
water required to keep the water in the collection basin at the required depth
depends upon the “evaporation loss” and “blowdown” .
FAN DRIVE–When using two-speed motors, allow a time delay of 20 seconds
minimum after de-energizing the high-speed winding and before energizing
the low-speed winding. Tremendous stresses are placed on driven machinery
and motors unless the motors are allowed to slow to low-speed RPM or less
before the low-speed winding is energized.
COLD WEATHER OPERATION–Duringperiodsoflowtemperatureoperation,
35°F to 40°F or below, ice will form on the relatively dry parts of the cooling
tower that are in contact with the incoming air. Primarily, this includes the air
inlet and adjacent structural framing. Your understanding of cold weather
➠

6
Caution
operation will be enhanced if you read “Operating Cooling Towers in
Freezing Weather” Marley Technical Report #H-003.
Ice forming characteristics on any given cooling tower will vary, depending on
velocity and direction of wind, circulating water rate, and heat load. Excessive
ice formation may be controlled by regulating air and water flow through the
tower by one or more of the following procedures:
1–Shut the fan down. This reduces the cooling air rate to a minimum and in-
creases the quantity of warm water at the air inlet to a maximum. However,
normal “fan off” operation causes reverse air flow by aspiration and may
cause water blowout and therefore must be done with caution and moni-
toring. For automatic operation, a timer switch can be provided to shut the
fan down for a few minutes each hour.
2–When a cooling tower has two-speed motors, operate the fans at half speed
forward. This reduces the cooling air rate (heat transfer) and increases the
quantity of warm water at the air inlet.
3–With no heat load on the circulating water, icing cannot be controlled. Towers
must not be operated with reduced water rate and/or no heat load during
freezing weather. If a bypass directly into the cold water basin is used, all
water must be bypassed.
Reverse operation of fans is not recommended . See “Fan Drive”
for fan speed change precautions.
INTERMITTENT OPERATION–When the unit is operated intermittently dur-
ing winter weather, it is necessary that the water be drained from the tower
piping to insure protection against freezing and possible rupture.
Tower Maintenance
Always shut off electrical power to the tower fan motor prior to
performing any inspections that may involve physical contact with
the mechanical or electrical equipment in or on the tower. Lock out
and tag out any electrical switches to prevent others from turning
the power back on. Service personnel must wear proper personal
protective clothing and equipment.
Well-maintained equipment gives the best operating results and the least
maintenance cost. SPX recommends setting up a regular inspection schedule
to insure effective, safe operation of the cooling tower. Use the schedule on
page 16 to obtain continuously good performance with the least tower main-
Warning

7
tenance. See Cooling Tower Inspection Check List in this manual. Keep
a continuous lubrication and maintenance record for each cooling tower.
HOT WATER DISTRIBUTION SYSTEM–Keep the circulating water and
distribution system (piping and nozzles) clean and free of dirt, algae, and scale.
Algae and scale may clog nozzles, eliminators, fill, and piping, and may collect
on the equipment served thus reducing its performance.
An access hatch in the fan deck with ladder to an intermediate platform pro-
vides means for inspection of the plenum area above the eliminators. Removal
of an access hatch at the plenum level allows access to the spray chamber
for inspection and maintenance of the nozzles and top of fill. Provide surface
protection before walking on the fill.
DRIFT ELIMINATORS–Eliminators should be kept clean.
Do not walk or step on the eliminators without planking and safety
harness.
COLD WATER COLLECTION BASIN (suppliedby others)–Inspectcollection
basin occasionally for leaks and repair if necessary. Keep cold water outlets
clean and free of debris. Makeup and circulating water controls must operate
freely and maintain the desired water quantity in the system.
DRIVE SHAFT–Check drive shaft alignment and condition of couplings every
six months. See the Drive Shaft User Manual for correcting misalignment,
balancing, or replacing parts.
ELECTRIC MOTOR–Lubricateandmaintaineachelectricmotorinaccordance
with the manufacturer’s instructions. If repair work is necessary, contact the
nearest representative of the motor manufacturer. See Warranty Section of
Marley Electric Motors User Manual.
FAN–Inspect fan blade surfaces every six months. For detailed maintenance
information, refer to Marley Fan User Manual.
GEAREDUCER–Make weekly and monthly oil checks. Inspect internal parts
during seasonal oil change. Refer to the Geareducer User Manual for detailed
maintenance instructions.
PAINTING–Periodically clean and, if necessary, recoat all metal parts subject
to corrosion.
Warning

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Water Treatment
BLOWDOWN–Blowdown, or bleed-off, is the continuous removal of a portion
of the water from the circulating system. Blowdown is used to prevent the
dissolved solids from concentrating to the point where they will form scale.
The amount of blowdown required depends upon the cooling range (the dif-
ference between the hot and cold water temperatures) and the composition
of the make-up water (water added to the system to compensate for losses
by blowdown, evaporation and drift). The following table shows the amount
of blowdown required to maintain different concentrations with various cool-
ing ranges:
BLOWDOWN–% OF CIRCULATING RATE
egnaRgnilooC snoitartnecnoCforebmuN
X5.1 X0.2 X5.2 X0.3 X0.4 X0.5 X0.6
)C°87.2(F°5 87.83.52.81.11.80.60.
)C°65.5(F°01 85.187.15.83.52.81.41.
)C°33.8(F°51 83.2 81.187.85.83.82.22.
)C°11.11(F°02 81.3 85.1 50.187.15.83.03.
)C°98.31(F°52 89.3 89.1 23.189.46.84.83.
.etarretawgnitalucricehtfo%20.0fotfirdnodesaberasreilpitluM
EXAMPLE: 7000 GPM circulating rate, 15° cooling range. To maintain 4
concentrations, the required blowdown is .38% or .0038 times 7000 GPM
which is 26.6 GPM.
If tower is operated at 4 concentrations, circulating water will contain four
times as much dissolved solid as the make-up water, providing none of the
solids form scale or are otherwise removed from the system.
CHEMICAL TREATMENT–In some cases chemical treatment of the cir-
culating water is not required if adequate blowdown is maintained. In most
cases, however, chemical treatment is required to prevent scale formation and
corrosion. Sulfuric acid or one of the polyphosphates is most generally used
to control calcium carbonate scale. Various proprietary materials containing
chromates, phosphates or other compounds are available for corrosion control.
When water treatment chemicals are required, the services of reliable water
treating companies should be obtained.
Slime, a gelatinous organic growth, and algae, a green moss, may grow in the
cooling tower or heat exchangers. Their presence can interfere with cooling
efficiencies. Proprietary compounds are available from water treating compa-
nies for the control of slime and/or algae; however, compounds which contain

9
copper are not recommended. Chlorine and chlorine containing compounds
are effective algaecides and slimicides. If used, chlorine should be added as
intermittent (or shock) treatment only as frequently as needed to control the
slime and algae. Chlorine and chlorine containing compounds should be added
carefully since very high levels of chlorine may occur at or near the point of
entry into the circulating water system.
FOAMING–Heavy foaming sometimes occurs when a new tower is put into
operation. This type of foaming generally subsides after a relatively short pe-
riod of operation. Persistent foaming can be caused by the concentrations of
certain combinations of dissolved solids or by contamination of the circulating
water with foam-causing compounds. This type of foaming can sometimes be
minimized by increasing the blowdown, but in some cases foam depressant
chemicals must be added to the system. Foam depressants are available from
a number of chemical companies.
MAINTENANCE OF FILL PERFORMANCE
Owner must keep water clean by treatment, screening, or filtering
to avoid the possibility of fill clogging and loss of thermal perfor-
mance.
Potential Causes of Fill Clogging:
• Suspended materials—Trash, etc.
• Scale—Can be sulfates, silicates, carbonates, or oxides. Scaling effects can
be accentuated by suspended muds.
• Algae and/or Slime—Can control with chlorine or non-oxidizing biocides.
Possible Sources of Scale:
• Calcium Sulfate—From make-up and sulfates produced by sulfuric acid for
pH adjustment. Calcium sulfate should be kept below 1000 ppm expressed
as CaCO3.
• Calcium Carbonate—Generally will not form scale in the cooling tower if
carbonate scaling does not occur in the condenser.
• Exceptions: If make-up water contains surplus free carbon dioxide, scaling
may be inhibited in the condenser, but may occur in the tower fill because
of CO2stripping.
• Silicates and Oxides—Silica scale is virtually impossible to remove. Silica
scale is unlikely if SiO2is held below 150 ppm. Oxides, such as iron oxide,
can coat all parts of the system if soluble iron is present in concentrations
above 0.5 ppm. Iron oxides do not usually develop into thick scales but can
accentuate the development of other scales.
Warning